Benefit: By voluntarily reducing your own AC, you can provide a deflection bonus to the AC of one or more allies against nearby opponents. As part of the attack action or full attack action, or as a separate standard action, you designate one ally who must be within your threat range. You grant that ally a bonus to AC equal to the amount by which you lowered your own AC, but only versus the melee attacks of opponents who are also within your threat range. For every 5 points of BAB above 5, you may designate one more ally within reach to receive this bonus (two allies at BAB +6, three allies at BAB +11, etc.) to a maximum of four allies at BAB +16. The bonus (and penalty) to AC lasts until the start of your next initiative, but ends for a target ally if they leave your threat range. You may only use this feat to grant a bonus to allies which you can see, and they do not benefit from the AC bonus against opponents that you cannot see. The maximum amount of AC that you may take as a penalty and grant to allies is equal to your Dexterity bonus to AC plus two. This value is limited by the maximum dexterity limit of your armor, so for instance, a character with DEX 18 (+4 bonus) wearing full plate (maximum dexterity bonus +1) would have an effective Dexterity bonus of +1 for purposes of this feat, and could reduce his AC by a maximum of 3 points to grant a +3 deflection bonus to AC. The AC bonus granted to allies is a Deflection bonus. Using this feat requires physical action, so a paralyzed character may not use it.

Special: When using the attack or full attack action, you may use both this feat and Combat Expertise simultaneously. A Fighter may select Defensive Expertise as one of his fighter bonus feats.